An array fluorescent biosensor based on planar waveguide for multi-analyte determination in water samples

A planar waveguide-based array immunosensor (PWAI) was described, allowing measurements of up to twenty-four analytes in eight separate channels rapidly, sensitively and simultaneously. In this system, a linear laser light created by a line generator was coupled into a planar optical waveguide via a beveled angle, forming eight individual total internal reflection (TIR) lines. A multi-channel microfluidics cell was employed to isolate the parallel TIR lines physically so as to form eight independent flow channels on the same chip, avoiding the cross-reactivity of antibodies and supporting various bioassay conditions. By employing fluorescent detection with fluorophore-labeled antibodies binding to the surface of the waveguide with the analyte derivative covalently attached, the array immunoassays can realize the multi-analyte biosensing. A model was proposed to guide the design of such a planar waveguide-based evanescent wave biosensor. The proposed system was confirmed with the comparable sensitivity with previously reported waveguide biosensor. In addition to being a multi-channel analytical device for the highly sensitive detection of contaminants, the proposed evanescent wave PWAI can provide the dynamic surface-based biomolecular interaction information regarding the affinity and kinetics with high sensitivity.